Back-flow preventer for water closets



March 6, 1962 T. H. LlTVlN 3,023,424

BACK-FLOW PREVENTER FOR WATER CLOSETS Filed July 21, 1959 20 v f W W,

/ ATTORNEYS.

United States Patent 3,023,424 BACK-FLOW PREVENTER FOR WATER CLOSETS Thomas H. Litvin, 3750 Lake Shore Drive, Chicago, Ill- Filed July 21, 1959, Ser. No. 828,575 1 Claim. (Cl. 4-74) This invention relates to a back-flow preventer for use with laterally discharging toilets or the like, and more particularly the back-flow preventer of this invention constitutes an improvement over present sweep connections used in waste disposal systems of the type herein described.

There are many instances in plumbing installations when it is desired to arrange a plurality of toilets in relatively close proximity to each other, and means must be provided for insuring proper receipt of the waste from said toilets. In certain installations of this type, the toilets are arranged to be wall mounted so that the discharge therefrom empties substantially laterally, and a single elongated waste-receiving, or drain, pipe is provided which extends transversely to the direction of discharge from the toilets, and which is adapted to receive the discharge from the plurality of toilets. In the latter installation, in order to insure no back-flow from the single waste-receiving pipe to any of the toilets, which may result during the flushing of other toilets coupled to said waste-receiving pipe, it is, at present, necessary to install, between each toilet and the waste-receiving pipe, a plumbing fitting which is known as a sweep fitting and which is of considerable cost and dimension.

The mere fact that the sweep fitting is of considerable dimension poses some serious construction problems, since the plumbing installations should be located in dead space between walls of building construction, and any factor that tends to increase the size of the dead space for receiving and housing plumbing installations will naturally have considerable bearing upon the total cost of the construction. Since it is an important problem to reduce the amount of dead space which plumbing systems occupy, it is, accordingly, one object of this invention to provide an improved waste disposal system wherein the plumbing connections, between laterally discharging toilets and a laterally running waste-receiving pipe to which said toilets are to connect, are of unusually small size as contrasted with sizes presently prescribed and existing for approved connections of the type herein described.

Another object of this invention is to provide a backflow preventer for use in plumbing systems which comprise laterally discharging toilets and laterally extending waste-receiving pipes to which the toilets are to empty, aid which back-flow preventer is characterized by the fact that it utilizes standard elbow fittings and Y fittings, thereby reducing the over-all cost of such an installation and maintaining the over-all dimensions of such an installation less than what would be required by existing specialized sweep fittings which are presently provided for such installations.

A further object of this invention is to provide a simple check valve means for use in a plumbing system comprising a laterally discharging toilet and a laterally extending waste-receiving pipe, which check valve operates to prevent undesirable back-flow from the drain pipe, and results in the provision of an eflicient but relatively inexpensive plumbing installation.

Further objects and advantages of this invention will become apparent as the following description proceeds and the features of novelty which characterize this invention will be pointed outwith particularity in the claims annexed to and forming part of this specification.

A preferred embodiment of the invention is shown in the accompanying drawings, in which:

3,023,424 Patented Mar. 6, 1962 FIGURE 1 is a top plan view of a portion of a plumbing system illustrating the environment of the invention herein disclosed as part of the connection of a plurality of wall mounted toilets to a laterally extending wastereceiving pipe;

FIGURE 2 is an enlarged view partly in elevation and partly in cross-section illustrating certain details of connection of a laterally discharging toilet to a portion of the back-flow preventer of this invention and showing the positioning of the check valve means therein;

FIGURE 3 is an enlarged detailed cross-section view illustrating the location and arrangement of the check valve in the system herein described; and

FIGURE 4 is a perspective view of the check valve shown in FIGURES 2 and 3.

Referring now to the drawings, there is illustrated in FIGURE 1 a plumbing installation which comprises a plurality of toilets 10 adapted to be mounted on one side of wall 12 of a building construction, which wall is provided with apertures 14 for accommodating plumbing connections to the discharge apertures of the toilets. Positioned on the other side of wall 12 is a laterally running elongated waste-receiving pipe, generally indicated at 16. The toilets 10 are adapted for lateral connection to the waste pipe 16, and, as best seen in FIG- URES 2 and 3, each toilet has a lateral discharge aperture 18 which opens in a direction substantially perpendicular to the longitudinal axis of the waste-receiving pipe 16.

The plumbing connection between each toilets discharge aperture 18 and the waste pipe 16 is designed not only to convey the waste from the toilet 10 to the waste pipe 16, but also to serve as a backflow preventer for insuring against any back-flow from the waste pipe 16 to any of the toilets 10, which back-flow might ordinarily result during the flushing of others of the toilets 10 Which are coupled to the waste pipe 16. Now the plumbing connection illustrated in FIGURE 1, between each toilet 10 and the waste pipe 16, includes a straight connector-pipe section generally indicated at 20, a standard elbow fitting 22 and a standard Y fitting, generally indicated at 24. The Y fitting is arranged so that its main throughway, which includes the stem of the Y and the one branch of the Y aligned with the stem, is interposed in the length of waste pipe 16, and successive Y fittings 24 are inter-connected by a length of pipe 26, so that the combination of sections of the Y fittings together with pipe lengths 26 define the waste pipe 16. The angled branch 28 of each Y fitting is connected to the standard elbow fitting 22, and said standard elbow fitting 22 is in turn, connected to the straight connectorpipe section 20. As seen in FIGURE 2, the connectorpipe section 20 comprises a nipple part 30, to which the elbow fitting 22 connects, and a pipe length 32.

Referring now to the details of the straight connectorpipe section 20, the nipple part 30 may be provided with a connector flange 31 adapted to lie against the back side of wall 12, and a plurality of elongated mounting bolt means 34 are provided, for extending through wall 12 and for clamping flange portions on toilet 10 and connector flange 31 to opposite sides of wall 12, so as to support the toilet 10 on wall 12 and to clamp connector pipe section 20 against toilet 10 in sealing relation. As best seen in FIGURES 2 and 3, the toilet is normally provided with an enlarged rim 33 surrounding the discharge aperture 18. Surrounding said rim 33 is a flattened, annular gasket receiving seat 36 which is surrounded by another enlarged portion 38 formed on toilet 10, thereby making the seat 36 depressed relative to the rim 33 and the enlarged portion 38.

The pipe length 32 is straight and has an upstream section 40 which is radially enlarged relative to the remainder of pipe 32, thereby defining an annular shoulder 42 that is spaced from and parallel to the plane of the upstream terminal edge 44 of the pipe 32. A first annular gasket means 46 is positioned in the enlarged pipe "section 40 against the annular shoulder 42. A check valve, generally indicated at 48, is positioned against said first annular gasket means 46; and a second annular gasket means 50 is provided upstream of the check valve 48 and extending upstream of the terminal edge 44 of the pipe 32, so as to be adapted to engage and seal against the seat 36 which surrounds the waste-discharging aperture 18 of the toilet 10.

The check valve 48 includes a rigid annular centering member, or ring, 52 of stainless steel or other corrosion resistant material. The size of the annular centering ring 52 is such that it remains centered with respect to the enlarged pipe portion 40. The radial width of the ring 52 is such that an inner portion of ring 52 extends inwardly of the gaskets 46 and 50, and the central aperture of ring 52 defines a waste-fiow-passing orifice 54 that is located radially inwardly of said gasket means. A gate member 56 is provided which is of a dimension greater than the orifice 54, but which is of smaller dimension than the first gasket means 46. The gate member is hinged on a hinge pin 60 carried on the downstream side of the inner, exposed, ring portion of the centering member 52, and a hinge plate 62 which carries the hinge pin 60 is spot welded or the like to the downstream side of ring 52, as best seen in FIGURE 4.

The arrangement is such that under normal non-flow conditions, the gate 56, under the influence of gravity, is in the normally closed position shown in FIGURE 3.

In the event of attempted back-flow from waste pipe 16 to a toilet 10, the gate 56 will clearly prevent such backflow. On the other hand, when the toilet is flushed, the gate 56 under the force of the waste flow from toilet 10 swings downstream within the straight length of the pipe 32 to an open position so as to afford substantially unobstructed discharge of waste flow from the toilet through the central opening 54 of the center member 52.

By the provision of the check valve 48 in the plumbing installation as herein described, it is possible to utilize a standard elbow fitting 22 and a standard Y fitting 24 in the installation of the wall, mounted toilet 10, and such arrangement has been found to avoid the'back-flow problems which have heretofore been solved only by installation of rather expensive and relatively large dimensioned sweep fittings. Thus, the instant arrangement of parts provides an efficient but relatively inexpensive plumbing installation which affords the desired and requisite protection against back-flow which has heretofore been ob tained only by relatively expensive and large dimensioned sweep fittings, while the instant installation is of unusually small size as contrasted with the space requirements of presently existing sweep connections.

While there has been shown and described a particular embodiment of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and, therefore, it is intended in the appended claim to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

A back-flow preventer for use in a plumbing system comprising a laterally discharging toilet and a laterally extending, elongated waste pipe extending transverse to the direction of discharge of the toilet; said back-flow preventer comprising, in combination: a horizontally extending straight length of connector-pipe for receiving waste flow from the toilet, a standard elbow fitting for receiving waste flow from the connector-pipe, a standard Y-fitting having its main throughway adapted to be interposed in said waste pipe and having its branch connected to the standard elbow fitting to define a waste flow discharge passageway of relatively small overall dimensions, and check valve means carried in said horizontal connector-pipe for preventing back-flow from said drain pipe into the toilet to which said back-flow preventer connects, said check valve means including an upstream section of said horizontal connector-pipe being radially enlarged and defining an annular shoulder spaced from and parallel to the plane of the upstream terminal edge of said connector-pipe, a first annular gasket means positioned in said enlarged pipe section against said annular shoulder, a rigid, annular, centering member positioned in said enlarged pipe section in engagement with said first annular gasket means and spaced downstream of the upstream terminal edge of said connector-pipe, a second annular gasket means engaging the upstream side of said centering member and extending beyond the upstream terminal edge of said connector-pipe and adapted to engage and seal against a seat surrounding a waste-discharging aperture, said centering member defining an annular exposed ring portion, surrounding a waste-tlow-passing orifice, located radially inwardly of both of said first and second gasket means, and a gate member, of smaller dimension than said first gasket means and larger than said orifice, hinged to the downstream side of said exposed ring portion of said centering member for pivoting about a horizontal hinge axis located vertically above the axis of said connector-pipe.

References Cited in the file of this patent UNITED STATES PATENTS 623,478 Keene Apr. 18, 1899 660,785, Bellows Oct. 30, 1900 1,093,626 Hulbert Apr. 21, 1914 1,460,986 Smith July 3, 1923 1,566,002 Hess Dec. 15, 1925 1,654,832 Pohl Jan. 3, 1928 1,725,428 Tilden Aug. 20, 1929 2,089,141 Wasserman Aug. 3, 1937 

